@Napoleon53 , if you ned to find a papal name for Mussolini and/or a teological ispiration for his actions, i would suggest you to use Saint Ambrose, saint patron of Milan.
Not only he was known for his persecutions against everything that wasn't chatolic including other christians,pagans and jews ( to the point he refused the idea that Jesus was jewish), but he also strongly believed that political power should be submissive to the Church.
Interesting enough Ambrose also believed that classical roman virtues could be still used if united with the teachings of the Bible so you could have Mussolini's obsession with imperial Rome even in this TL